The exact nature of the curse differs in various accounts of the incident. Some state that Sianis declared that no World Series games would ever again be played at Wrigley Field, while others believe that his ban was on the Cubs appearing in the World Series, making no mention of a specific venue. Sianis’ family claims that he dispatched a telegram to team owner Philip K. Wrigley which read, “You are going to lose this World Series and you are never going to win another World Series again. You are never going to win a World Series again because you insulted my goat.”[citation needed] Whatever the truth, the Cubs were up two games to one in the 1945 Series, but ended up losing Game 4, as well as the best-of-seven series, four games to three. The curse was immortalized in newspaper columns over the years, particularly by syndicated columnist Mike Royko, and gained widespread attention during the 2003 postseason when Fox television commentators played it up during the Cubs-Marlins match-up in the 2003 National League Championship Series.[3] (According to an account in the Chicago Sun of October 7, 1945, the goat was turned away at the gate, and Sianis left the goat tied to a stake in a parking lot and went into the game alone. There was mention of a lawsuit that day, but no mention of a curse.)

Sam Sianis, nephew of Billy Sianis, has been brought out onto Wrigley Field with a goat multiple times in attempts to break the curse: on Opening Day in 1984 and 1989 (in both years, the Cubs went on to win their division), in 1994 to stop a home losing streak, and in 1998 for the Wild Card play-in game (which the Cubs won).[4]

In 2003 (incidentally, the Chinese zodiac's Year of the Goat), a group of Cubs fans headed to Houston with a billy goat named "Virgil Homer" and attempted to gain entrance to Minute Maid Park, home of the Astros, division rivals of the Cubs at the time.[5] After they were denied entrance, they unfurled a scroll, read a verse and proclaimed they were "reversing the curse." The Cubs won the division that year and then came within five outs of playing in the World Series, but were undone by the Florida Marlins' eight-run rally immediately following the Steve Bartman incident. The Cubs then lost the following game and with it the series. (The Marlins went on to win the World Series against the New York Yankees). Further salting the wound, the Astros earned their first World Series berth two years later (they would be swept by the Cubs' crosstown rivals, the Chicago White Sox).

In another bizarre twist, it was reported that a butchered goat was hung from the Harry Caray statue on October 3, 2007, to which The Chicago Sun-Times noted: "If the prankster intended to reverse the supposed billy goat curse with the stunt, it doesn't appear to have worked."[6] While the Cubs did win the NL Central division title in 2007 and 2008, they were swept in the first round of the postseason in both years: by the Arizona Diamondbacks in 2007 and the Los Angeles Dodgers in 2008. The elimination by Arizona came on October 6, the same date that the goat appeared at Wrigley Field in 1945.[7]

The act was repeated before the home opener in 2009, this time a goat's butchered head being hung from the statue. The act was futile as the Cubs were eliminated from postseason contention on September 26, 2009.[8] Cubs fans have also brought in priests that have blessed the field, stadium, and dugout.

On April 1, 2011, a social enterprise called Reverse The Curse, dedicated to bringing innovations to poverty by giving goats to families in developing countries, was initiated.[9] The goats provide the family with milk, cheese, and alternative income to help lift them out of poverty.

On April 10, 2013, a severed goat's head was delivered to the Cubs in a possible effort to lift the curse on the team. It was addressed to the club's owner Thomas S. Ricketts.[10]

According to three interviews with Sam Sianis, William Sianis' nephew, the Curse of the Billy Goat can be dispelled only by the Chicago Cubs organization's showing a sincere fondness for goats; allowing them into Wrigley Field because they genuinely want to and not simply for publicity reasons.[citation needed]

Popular fictional character Harry Dresden, wizard, discovered the "true" story behind the curse. Author Jim Butcher shared the tale in "Curses", included in the short story collection Naked City: Tales of Urban Fantasy by Ellen Datlow published in 2011. Wizard Dresden discovered the goat at Wrigley Field was actually Gwynn ap Nudd disguised as a goat, and the baseball fanatic King of the Tylwyth Teg issued the curse when he was not allowed to watch the game.